Refrigeration system



Jan. 15, 1946. I v B. E. SHAW EIAL 2,393,123.

REFRIGERATION SYSTEM Filed Sept. 16, 1941 scriptlon and to wherein such furtherobiects will definitely ap- Patented Jan. 15, 1946' UNITED REFRIGERATION SYSTEM Burton E. Shaw, Bristol, and' Wilbur w. Wood, Goshen, Ind., assignors to Penn Electric Switch 06., Goshen, Ind., a corporation of Iowa Application September 16, 1941, Serial No. 411,028

9 Claims.

Our present invention relates to a refrigeration system wherein two-temperature control .is secured from air and refrigerant temperatures and wherein both a refrigerant compressor motor and a fan motor are controlled by the two temperatures in a novel interlocking manner.

- A further object is to provide a refrigeration system wherein a pair 01' controls are provided and so interlinked with each other that one of them, responsive, to circulated air temperature, controls an air circulating fan and the other one, responsive to condition of the refrigerant, controls the refrigerant motor as to energizing it only, a

mechanical connection being provided between with which a magnet 28 coacts for ivi p the fan switch and the.compressor motor switch for opening the circuit of the motor switch wheni ever the fan switch circuit is opened. Y

Another object is to provide means whereby a pair of pressure ortemperature operated control r justable screw 26 in the lever 22. The bell crank switches may control a refrigerant compressor motor and an air circulating fan motor in a manner that is desirable for the automatic operation of each motorand in a manner to secure defrosting of the evaporator coils each cycle of opera-'- tion of the control devices, and at the same time increase the efllciency of the refrigeration system by the operating of an air circulating fan at only advantageous periods of time as determined by temperature conditions; g

with these and other objects in view, our invention with respect to its features which we'believe to be novel and patentable will be pointed out in the claims appended hereto. For a better detailed understanding of the invention, and further objects relating to details of economy of our invention, reference is made to the following dethe accompanying drawin pear, and in which Figure l is a diagrammatic view of a refrigeration system embodying our invention and showingthe parts in "dormant-position, and

Figures 2, 3 and 4 are similar diagrammatic he views of the switch structures only of the system,

showing the different positions assumed during different periods of the operating-cy le.

On the accompanying drawing, we have used 1 the reference character It to indicate a chamber wherein an evaporator E is mounted for cooling the space within the chamber. The chamber Ill may be a butcher box .or the like. The evaporator E- is supplied with refrigerant from a compressor 7 C and a condenser C. The usual expansion valve of the refrigerationsystem is indicated at V.

A motor M is provided for operating the refrigi a (on sti) ,f

erant compressor C. For circulating airin the chamber Hi, we provide a fan I consisting of a motor I2 and fan blades 12. For controlling the motors M and i2. weprovide a motor switch MS l9 and connected by a toggle spring 2ll with a lever 22. The lever it constitutes an armature action to the fan switch as The lever 22 is pivoted at 21 andis operated by a bell crank 24 pivoted at 2B. The bell crank 24 has a lost motion connection including an ad- 24 is urged into contact with the diaphragm I! by a range spring 2-1, which spring is adjustable.

by a manual control indicated at 28. The control 2! is preferably mounted where it can'be readily 25 operated by the user of the refrigeration system.

I The motor switch MS includes a pressure chamber 29, a diaphragm ill, a capillary tube 2!, and a capillary bulb l2 responsive to evaporator temperature. The linkage between the dia- 0 phragm so and the motor switch MS includes an,

arm 33 pivoted at and constituting an armature coacting with a magnet 35 for snap action purposes. The linkage for the diaphragm "further includes a bell crank lever 36 pivoted at 31' 35 and connected by a toggle spring 28 with, the

lever 23. An adjustable stop 2! is provided for the bell crank 36 and a range spring is also provided therefor. Thera'nge spring 40 is adlusted by a screw ll which together with the 40 screws 26 and II are preferably available to the I service man only.

A mechanical conn in the form of an arm 42 and operable through 45 a set screw 43 to engage the lever 32 and open the switch MB against the tension-of the toggle spring 3! whenever the fan switch F8 is open.

Practical operation and-22 have been satisfied as torequirements for air circulation and refrigerant circulation, the.

parts may assume the position shown in Figure 1,

with switches rs and both In the its capillary bulb l1 and 10 the necessary mechanical linkage between the ticn between the run switch F5 and the motor switch MS is provideddormant position, the bell crank lever 88 may be eitherin the full line position illustrated, or in the dotted line position illustrated.

As theair temperature increases it will affect the bulb [1, thereby causing the diaphragm ii to be pressed upwardiy as in Figure 2 to first take up the lost motion between the bell crank 24 and the adjusting screw 26, and then snap the toggle spring 20 overcenter to close the switch ES. The toggle springs 20 and 38 in Figures 2, 3 and 4 have been indicated by dotted lines to avoid confusion on the drawing. Closure of the fan switch FS removes the set screw 43 from motor switch opening position, but whether the diaphragm 30 is in lowered position or in slightly raised position, shown by the dotted lines in Figure 1, the motor switch will remain open due to the toggle spring 38 being in a position tending to rotate the arm 33 counterclockwise. It is undesirable to operate the motor M until after frost on the coil E has been melted. I'his is accomplished by the proper location of toggle centers for the spring 38, the screw 39 being adjusted to secure the desired result.

Circulation ofthe air in the chamber l by the fan F causes the temperature around the evaporator E to rise and to melt any frost that may be thereon. By way of example, the fan switch FS may close in Figure 2 at an air temperature of 36 and consequent operation of the fan F then raises the coil temperature from below freezing to 35 At 35, the bulb 32 will have caused sufiicient pressure on the diaphragm 3D to move the bell crank lever 36 toward the right to the Figure 3 position to effect closing of the motor switch MS due to the toggle spring 38 being in position tending to rotate the arm 33 counterclockwise. The compressor C will now operate and lowerthe temperature of the evaporator and the air being circulated. For instance, the air may be lowered to 34 and the coil to 33, whereupon the bulb 32 may attempt to open the motor switch as in Figure 4. The stop screw 39, however, is adjusted to a position where the toggle spring 39 cannot pass center and the motor switch accordingly remains closed so that refrigerant compressor operation continues as long as air circulation is had. Finally, when the air temperature goes down to 33", it will so affect the bulb 11 as to permit the diaphragm IE to change from the position of Figure 4 to the position of Figure 1, thus shutting off the fan switch. Due to the mechanical connection 42, the motor switch will be simultaneously cut oil with the fan switch instead of the usual operation of cut-off when the bulb I! is satisfied.

If after the position of Figure 3 is assumed the air temperaturegoes down to 33 before the coil temperature does, then the bell crank will remain in the position of Figure 3 (dotted position of Figure 1) and the motor switch will be opened again by openingof the fan switch, regardless of the temperature of the bulb 32. 'This mechanical interlocking arrangement coupled with the motor switch MS having a narrow differential and the fan switch FS having a wider differential, gives multaneously. Such an arrangement effects economy in current consumption for the circulating fan, in expense of the fan motor, and a reduction in expense as compared with continuous displacement of cold air when the doors of the chamber III are opened. It is also advantageous to control the fan so that it starts at some temperature or pressure to defrost the coils, and when this has been accomplished then the compressor unit commences to operate. Finally, both the fan switch and the compressor switch out out simultaneously when the chamber I! has cooled to a predetermined temperature.

Some changes may be made in the construction and arrangement of the parts of our device without departing from the real spirit and purpose of our invention, and it is our intention to cover by our claims any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope without sacrificing any of the advantages thereof.

We claim as our invention:

1. A refrigeration system including an evaporator, a compressor for supplying refrigerant thereto, a motor for operating said compressor, a. fan for circulating air in the space being cooled by said evaporator, a motor for said fan, and control means for said motors, said control means comprising a fan motor switch responsive to the temperature of the air being circulated, and a compressor motor switch responsive to evaporator temperature for cut-in and responsive to the temperature of the air being circulated for outout.

2. In a refrigeration system, an evaporator, a compressor for supplying refrigerant thereto, a motor for operating said compressor, a motor and fan for circulating air in the space being cooled by said evaporator, and control means for said compressor and fan motors, said control means comprising a fan motor switch responsive to the temperature of the air being circulated, a compressor motor switch responsive to the temperature of the refrigerant leaving said evaporator and operable to two opposite positions, said compressor motor switch closing only in response to a rise in the temperature of the refrigerant, and said fan switch upon operation to one of its positions opening said compressor motor switch.

3. In a refrigeration system, an evaporator, a

. compressor for supplying refrigerant thereto, a

motor for operating said compressor, a motor and fan for circulating air in the space being cooled by said evaporator, and contro1 means for to refrigerant temperature, said compressor mothe type of control referred to above in connection with the operation of our refrigeration system; The results obtained are the employment of forced circulation to effect defrosting of the evaporator prior to operation of the compressor,

with operation of the compressor continuing until tor switch closing in response to refrigerant temperature rise and. opening when said fan switch opens, and a mechanical connection between said fan motor switch and said compressor motor switch effecting such opening of said compressor motor switch. 1

4. In a refrigeration system, an evaporator, a compressor for supplying refrigerant thereto, a motor for operating said compressor, a motor and fan for circulating air in the space being cooled by said evaporator, and control means for-said motors comprising a fan motor switch and I. compressor motor switch for said fan and compressor motors, respectively, said fan motor switch being operable to close and open the circult of said fan motor in response to the temperature of the air being circulated, said fan so r switch operating independently of said compressor motor switch, said compressor motor switch being operable to close the circuit of said compressor motor in response to refrigerant tern: perature rise independent of said fan motor;

switch, and means operable to open the circuit of the compressor motor, said means being oper. ated by said fan motor switch as it moves from Y closed to open position.

5. A refrigeration system including an evaporator, a compressor for supplying refrigerant J perature of the air being circulated independently of said compressor motor switch, said compressor motor switch .being operable to close the circuit of said compressor motor in response to the evaporator temperature rising to a predetermined point independent of said fan motor switch, and. means operable to open-said compressor motor switch, said last means being connected with said fan motor switch to be moved to compressor motor switch opening position thereby when the -fan motor switch moves to its open position,

- 6. Control means for a refrigeration system motor in responsatothe' temperature of the refrigerant being supplied by a compressor driven by said compressor motor, said compressor motor r switch closing independent of said fan motor switch, and an interconnection between said compressor motor switchand said fan motor switch for opening the compressor motor switch when the 1 an motor switch opens.

8. A refrigeration system including an evaporator, a compressor for supplying refrigerant thereto, a motor for operating said compressor, a fan for circulating air in the space being cooled by said evaporator, a motor forsaid (an, and

- control means for said fan motor and said compressor motor, said control means comprising a fan motor switch for said fan motor responsive tothe temperature of the air being circulated, a compressor motor switch for said compressor motor responsive to evaporator temperature, said compressor motor switch moving toclosed position only in response tothe temperature rising to a predetermined point, and a mechanical connection between said switches ior moving said compressor motor switch to open position simultaneously with the opening of said fan motor switch ,in response to, the temperature of the air being circulated lowering to a predetermined comprising a fan motor switch and a compressor motor switch, said fan motor switch being responslve to air temperature and operable to close and open in response to high and low temperature, respectively, said compressor motor'switch being'responsive to refrigerant temperature and moved to closed position thereby-and a mechanicaiconnection 1 between said compressor motor switch and said fan motor switch for opening said compressor motor switch in response to opening of said fan motor switch.

I 7. Control means for a fan motor and a refrigerant compressor motor comprising a fan motor switch and a compressor motor switch, said fan motor switch being operable to close and open the circuit of said fan motor in response to air temperature, said fan motor switch operating,

independently of said compressor motor switch, said compressor motor switch being'operable to close the circuit of'said reirigerant compressor 9. In a refrigeration system including an evaporator, a compressor for supplying refrigerant thereto, a motor for operating said compressor, a

fan-for circulating air in the space being cooled by said evaporator, a motor for operating said fan, and control means for said fan motor and compressor motor comprising a fan motor switch and a compressor motor switch, said fan motor switch being responsive to circulated air temperature and operable to close and open in re-.-

sponse to high and low temperature, respectively, said compressor motor switch having a portion responsive to refrigerant temperature and operable at a predetermined point during refrigerant temperature rise to move said compressor motor switch to closed position only, and a mechanical connection between said compressor-motor switch and said fan motor switch for opening the compressor motor switchby opening of the fan motor switch.

' BURTON E. SHAW.

WILBUR-W. WOOD. 

